It uses very common building blocks. The high voltage power supply is a classical oscillator circuit used in many places where a low current and high voltage is needed. TR is a step-up transformer salvaged from a xenon light circuit. You can find simmilar transformers in fluorescent tube portable flashlights and simmilar devices using battery oper
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ated fluorescent tubes. T is a common NPN transistor. Many transistors will work in this circuit. I used a 2SD1207 just because I found it in my junk box. Test some different transistors. Ones seems to work better that others in this kind of oscillators. D is a fast switching high voltage diode. I used a RG1M fast switching diode from an old TV set. Don`t use 1N4007, it works fine at 50/60 - 100/120 Hz but fails at several kHz. This simple high voltage power supply is stable enough if input voltage is stable, so I placed a 78L33 regulator in front of it. This limits the minimum Geiger`s supply voltage to around 5 volts. The output voltage can be adjusted with the aid of the 22k variable resistor from about 200 up to 800 volts. The tube used is a ZP1401 from Mullard, almost identical to the LND 712 useful to detect alphas, betas and gammas. RSense and RLoad are taken from the LND 712 datasheet (1 and 10 Mohms) in the same way as the operating voltage (500 volts). The rest of the circuit is the UGP interface (the rightmost gate in schematics) from where the RS232 signal is taken. This signal is feed also into asimple monostable circuit to produce nice beeps and led flashes with every count. The circuit was mounted into an aluminum box with a hole to get alpha particles to get into the tube mica window. To protect this extremally delicated mica window a wire mess cut from a desktop pencil bucket was used with great success. I...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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